The present invention relates to an optical disc apparatus and a tracking control method.
One of documents regarding tracking control is JP-A-2008-299963 (Patent Document 1). The background art of this Patent Document 1 describes that “First, track-crossing frequency due to an eccentricity of an optical disc is detected when the tracking servo is turned off; and then the tracking servo is turned on, i.e., track pull-in is performed when the track-crossing frequency reaches the lowest value (i.e., when the track is displaced, due to the eccentricity, at maximum toward the inner circumference side or the outer circumference side of the optical disc) and also when an objective lens is not moved from its neutral position.
Subsequently, a tracking actuator is activated to start tracking control by having the objective lens follow the track and moving the objective lens toward the radial direction of the optical disc. Thereafter, the neutral position of the objective lens is moved to a center position of the track displaced due to the eccentricity of the optical disc by activating a slider based on an average value of a driving signal for the tracking actuator per one revolution of the optical disc.
Then, the tracking control is performed by moving the objective lens to make it follow the track”.